SEER update of incidence and trends in pediatric malignancies: acute lymphoblastic leukemia.

BACKGROUND

Acute lymphoblastic leukemia (ALL) represents the most common malignancy of childhood. Its incidence peaks in children just before school entry age; i.e., in 2-3 year olds. It is known to be more common in white children in the USA; the incidence is also higher in boys than girls.

PROCEDURE

We reviewed the 5,379 cases of ALL among persons under 20 years of age in the National Cancer Institute's Surveillance Epidemiology and End Results (SEER) database.

RESULTS

The overall incidence of ALL was 26/10(6) person-years between 1973 and 1998, but increased from 19/10(6) person-years in 1973-77 to 28/10(6) person-years in 1993-98 (P < 0.0001). Rates were 44% higher among Whites compared to Blacks (27/10(6) person-years vs. 15/10(6) person-years, P < 0.0001). In 1992-1998, the incidence rate for Hispanics was 43/10(6) person-years, significantly higher than non-Hispanics (28/10(6), P < 0.0001). White children with ALL had better 5-year survival rates than Black children with ALL (71% vs. 58%, P < 0.0001), and 5-year survival was poorest among black males.

CONCLUSIONS

ALL incidence has increased over the examined 25-year period. The rate in US whites is higher than that of US Blacks, and the rates in the Hispanic subgroup are the highest of all. While the median survival period is now more than 10 years overall, the 5-year survival rate remains poor for Black males under 4 years of age. Socioeconomic factors do not account for this difference, which may relate to ALL subtype distribution.